Ralf Erens Editor

Carola Bernack-Schüler and Ralf Erens are PhD candidates and research assistants at the Institute of Mathematics Education at the University of Education Freiburg. Prof. Dr. Andreas Eichler and Prof. Dr. Timo Leuders are researchers at the Institute of Mathematics Education at the University of Education Freiburg. Andreas Eichler has recently changed position to the University of Kassel.